2 Fuel use, CO2 and costs fall 12%3. German 30km/h (18.6 mph) zones led to car drivers changing gear 12% less often, braking 14% less often and using 12% less fuel.

3 Less Congestion. At 20 mph more cars occupy the same road space due shorter gaps between them relative to 30 mph, easing traffic ‘flow’. Junctions are more efficient as drivers can merge into shorter gaps. Less risk encourages sustainable travel and public transport.

5 Cleaner air quality especially benefits motorists. They breathe in-car air which is three times more polluted than at the pavement4. Standing traffic, which produces unnecessary fumes, reduces as traffic flow becomes smoother. Less fuel is burnt due to less acceleration and the transfer of some trips away from cars towards walking, cycling and public transport.

6 Motoring costs drop. As crashes fall in severity and frequency, so do legal and repair bills. This will be reflected in motor insurance premiums dropping in 20 mph limit post codes.

8 Stress reduces as drivers have more time to see and react to hazards. Fewer road rage incidents occur due to more considerate driving styles, including less dangerous overtaking and it is easier to pull out. With casualties down by 22% some drivers will suffer less emotional trauma and anxiety from their part in liability for crashes. Noise also reduces.